In an irrigation system, drip zones are generally smaller, non-turf areas such as flowerbeds, ground cover, street medians, vegetable gardens and hanging baskets requiring a more precise amount of water delivered at or near plant root zones. Such areas are commonly watered with drip emitters, bubblers, micro-sprays, and other low-volume emission devices. These watering devices provide precise amounts of water and promote healthier plants and reduce the amount of water run-off and overspray into unwanted areas.
These watering devices are generally designed to provide a set amount of water over a predetermined ground surface area. Each particular device, however, may not be robust enough to efficiently water areas and types of vegetation for which they were not designed. For instance, a watering device designed to efficiently water a flower bed of a first area may not be suitable to efficiently water a vegetable garden of a larger, second area. Furthermore, a spray nozzle designed for a predetermined flow rate and pressure may not achieve desired distribution uniformities or precipitation rates for different flow rates and pressures.
A common shortcoming of typical watering devices, especially low-flow devices designed for drip zones, is the inability to customize the throw distances, fluid streams, spray patterns, or other fluid distribution properties once the sprinkler is installed in response to changing environmental conditions or fluid parameters. Prior attempts to provide customized distributions in an irrigation sprinkler are either cumbersome or do not project a fluid stream or spray in an efficient manner over a wide fluid flow rate or pressure range (i.e., achieving poor distribution uniformity or precipitation rates). For instance, it has been attempted to impart flexibility into a spray head using a rotating disk with multiple orifices of a different diameter to vary the flow and pressure upstream of a nozzle. Another attempt includes a rotary guide that increases the angular spray pattern in response to the circumferential position of the guide. (i.e., a 15° spread is watered upon a 15° rotation of the rotary guide, a 30° spread is watered upon a 30° rotation of the guide, and so forth.) Such spray heads, however, are still constrained with a fixed nozzle and, therefore, a fixed spray pattern that may not be efficiently designed for changes in flow rates or pressure, especially at low flows.
Other irrigation sprinklers attempt to incorporate multiple nozzles to project different spray patterns depending on which nozzle is aligned with the fluid stream. Such designs, however, are bulky and cumbersome and are not suitable for the low-flow, drip irrigation zones. These designs also require protective hoods that may interfere with the spray pattern or include multiple off-center components to house the multiple nozzles that may render the nozzle unstable and visually unpleasing for use in an irrigation system.
Accordingly, it is desired for an irrigation sprinkler that is configured to provide a selectable fluid distribution suitable for low-flow, drip irrigation zones.